multiple pxe servers on same network

Paolo Rivetti paolo at
Tue May 17 07:05:56 UTC 2011

Hello everyone
I am using the ISC DHCP server as a PXE server on the network from one 
year inside a computer lab.

I wish I could insert a second PXE server on the same network 
( To these two PXE server, it connects multiple clients 
every week. I can not use the trick of mac addres to assign a client to 
a server rather than another.
Reading wikipedia it seems that you can send a DHCOFFER with a list of 
"" If a PXE redirection service (Proxy DHCP) Receives an extended 
DHCPDISCOVER, it replies by with an extended DHCPOFFER to the client to 
port 68/UDP (DHCP client port).

An extended DHCPOFFER Mainly contains:

PXE Discovery Control field to recommend multicasting, broadcasting, 
unicasting or to contact the PXE boot servers
a list of IP addresses available Each of PXE Boot Server Type
PXE Boot Menu With Each entry Representing a PXE Boot Server Type
PXE Boot prompt telling the user to press a key Certain to see the boot menu
a timeout to launch the first boot menu entry if it expires

The Proxy DHCP service run May Also On The Same host as the standard 
DHCP service. Since two services can not share port 67/UDP, the Proxy 
DHCP runs on port 4011/UDP and Expects the extended DHCPDISCOVER packets 
from PXE Clients to be DHCPREQUESTs. The standard DHCP service has to 
send a special combination of PXE options in ITS DHCPOFFER, I know the 
PXE client knows to look for a Proxy DHCP on the Same host, port 4011/UDP. "

How can you do this

Thanks, Paolo

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